Steep the tea bag in 50ml boiling water for 1 minute, remove the bag.
Place the milk, chia seeds, oats, raspberries (reserving a few for garnish) and tea in a small saucepan and bring up to a simmer, cook gently for 2-3 minutes, stirring. Cool slightly.
Stir in the 2 tbsp yogurt, transfer to 2 serving dishes and cool for 30 minutes or longer.
Top with remaining yogurt and raspberries and sprinkle over the seeds.